Electrically-heated device



March 6, 1928. 1,662,031

F. H. MCCORMICK ELECYRICALLY HEATED DEVICE Filed Sept. 11, 1925 4 A i: I n\/entor*:

Francis H. McCormick,

m5 Attorney.

Patented lVlar. 3, i928.

UITED tee-zen arise.

FRANCIS H. MoCORMICK, or amen ELLYN, ILLINQIS. ASSIGNOR are EEDISON unscrew APPLIANCE COMPANY, me, or carcass, ILLINOIS, a conrona K YORK.

ELECTRICALLY-HEATED DEVICE.

Application filed September 11, 1925. serial 220. 55,822.

My invention relates to electrically heated The contactor 14 is operated by a coil 17 devices, and has for its object the provision which is connected to the supply source 13 of improved controlling means for such dein circuit with a temperature responsive devices. vice shown as a thermostat 18. This ther- More specifically, my invention relates to mostat is exposed to the heat of the o en to electrically heated devices, such as ovens and operates to open the circuit of the coil and the like, in which suitable mechanism 17 upon the occurrence of a predetermined is sometimes provided'for automatically apmaximum temperature and close its circuit plying and cutting off the heat at predeterupon the occurrence of a predetermined minmined times such, for example, as described imum temperature, whereby a predetermined B5 and claimed in Patent 1,495,045, to Rankin, mean temperature is maintained in the oven. dated May 20, 1924. p In order to provide for the connection of In one of its aspects my invention relates suitable time control means 19in circuit with to an arrangement or an attachment wherethe thermostat 18, stationary resilient conby the oven or other heated device may tact clips 20 and 21 are provided the clip 20 to be manufactured with standard equipment being connected directly to the fixed contact without the automatic control mechanism, 18 with which the thermostat cooperates special connecting means being provided while the clip 21 is connected through a; whereby the automatic control mechanism, conductor 22 to the side of the supply source 20 which is' also manufactured as a separate de- 13 opposite to that to which th th t t 75 vice, may be connected if desired. This ohis connected. The clips 20 and 21 carry reviously avoids the necessity of having two silient contacts 23 and 24 respectively, which standardized sets of devices, one equipped are arranged to engage each other normally with automatic control and the other withand thus close a circuit from the contact 18 25 out. Furthermore, the automatic equipment to the supply source. A third stationary 8c may be added subsequently at any time. clip 25 is also provided. This cli is con For a more complete understanding of Elect d the same side of the supp y source my invention, reference should be-had to the the thermostat. As shown in Fig. 3, accompanying drawing in which Fig. 1 is the contact clips 20, 21 and 25 may cona diagrammatic representation of an electric veniently be secured on a base member 26 oven provided with control means embodymade of porcelain or other electrically ining my invention, while Figs. '2 and 3 are Sula ed material, the clips being secured in detailed views showing the electrical con- Suitable apertures 20, 21 and 25 in the ti axm member whereby contact ins may be 35 Referring to the drawing, I have shown s d nto engagement with t em.

my invention, in one form as applied to an time control mechanism 19 has its electrically heated oven 10, indicate inals connected to three contact pins 27,

dotted lines, which is provided with heating 0 and 22 which are arranged to engage with resistors 11 and 12. The resistors 11 and 12 the contact clips 20, 21 and 25 respectively.

are energized from a suitable electrical sup- These Contact pins may conveniently be seply source 13 a contactor switch 14 being cared to a supporting member 30 (Fig. '2)

included in the circuit with the resistors. made of suitable electric insulating mate- Suitable three-heat switches 15 and 16 are rial and having a central aperture 31 also connected in circuit with the resistors through which conductors may extend for 11 and 12 respectively whereby the connec connection with the pins. To assure the intions may be varied to change the rate of sertlon of the pins into contact with the heat generation in a well known manner. respective clips as previously indicated, the

As shown, each resistor is divided into two clips 20 and 21 are arranged nearer to each sections, the connection of which is conother than to the third clip 25,- the pins 27 trolled by the switches 15 and 16 in such and 28 being similarly arranged with respect manner that both sections of each resistor to the pin 29. Furthermore, the arrangemay be connected in parallel to the supply meat is such that tile insertion of the pins source for high heat, and in series for low 27 and 28 into the clips 20 and 21 springs heat, one section only being connected for the clips outward slightly, enough to sepintermediate heat. agate the two contacts 23 and 24 whereby no the time control mechanism is inseited in circuit with the thermostat 18. When the time control mechanism is removed the contests 23 and 24 reengage to maintain the thermostat circuit. As shown, each contact clip is provided with two resilient jaws between which the pins 27 and 28 are forced, the outer jaws of the clips 20 and 21 carrythe contacts 23 and 24. I

Vi hile any suitable time control mechanism may be used I have shown for the purpose of illustration the mechanism d sclosed in the aforesaid patent to Rankin. This mechanism consists, briefly, of a constant speed electric motor 30 of eddy current type which drives two pinions 31 and 32, these pinions being shownas mounted on the shaft of the motor. The pinions cooperate with two gear wheels 33 and 34 which are provided with mutilated sections or blank spaces 35 and 36 on their perlphcries whereb when a pinion 31 or 32 arrives at a b ank space no further rotation of the particular gear wheel takes place. The gear wheels are also provided respec tively with apertures 37 and 38 near their peripheries, which apertures are adapted to receive pins 39 and 40 mounted upon resilient switch members 41 and 42. These switch members cooperate with stationary contacts 43 and 44, the switch member 41 being in engagement with the contact 43 when the pin 39 falls in the aperture 37, and the switch member 42 being normally in engagement with the contact 44 and breaking contact when the pin enters the aperture 38.

The ear wheel 33 is secured to a shaft 45 whic 1 is provided with a pointer 46 and may be turned b means of a knurled knob 47. The gear w eel 34 is similarly secured to a sleeve 48 which is concentric with the rod 45 and carries a pointer 49 together with a knurled knob 50. The shaft 45 and the sleeve 48 are mounted so that they may be moved axially toward the left by pressing upon the knobs 47 and 50 and are normally forced toward the right so that the gear wheels mesh with the respective pinions by means of springs 51' and 52. As shown, the switch arms 41 and 42 are electricall connected in series with the motor 30 an by way of conductor 53 to the contact pin 29. The contacts 43 and 44 are connected respectively to the pins 27 and 28.

After the time control mec anism has been cornected by inserting the contact pins in the cli s, the electrical connections'and the operation of the device is substantially as described in the aforesaid patent to Rankin. Assuming that the operator wishes to have the resistors automatically connected to the supply source at 4- oclock so that the oven will be heated and that it is desired that the current be turned off at 6 oclock, the

operator will press inward on the knob 47 to free the gear wheel 33 from the pinion 31 and then turn the knob until the pointer 46 indicates 4 oclock on a suitable stationary dial 54. The gear wheel 33 is then moved back by the spring 51 into engagement with the pinion 31. Since the apparatus has been left in a position so" that the pin 39 is in the aperture 37, by turning the gear wheel 33 the pin 39 is caused to ride on the face or side of the gear wheel whereby the switch member 41 is moved to disengage the contact 43. In like manner, the pointer 49 is turned to indicate 6 oclock, the time when the circuit is to be opened, and the switch member 42 is thereby caused to engage the contact 44 whereby the motor circuit is closed. This starts the electric motor. The motor continues to o crate and at 4 oclock the gear wheel 33 wil be turned to such a position that the pin 39 will enter the aperture 37 whereby the circuit is closed throu h the coil 17 of the contactor switch and the heating resistors thereby connected to the supply circuit, the thermostat being then in engagement with the contact 18, since the oven is cold. As the oven heats up the thermostat will operate as previously described to maintain a predetermined desired temperature. When the hour of 6 oclock arrives, the aperture 38 will have been moved in front of the pin 40, which will thereupon enter the aperture 38, whereby the switch member 42 is caused to disengage the stationary contact 44 and open the control circuit. This stops the electric motor 30 and deenergizes the contactor coil 17 whereby the heating resistors are disconnected.

By means of this arrangement the oven is constructed with the thermostatic control only and the time mechanism constructed separately as an attachment which may be added subsequently as desired by simply plugging in the contact pins.

It will be observed that the current to run the motor 30 is carried through the contact clip 25. In case a spring operated timer mechanism is used, thls clip is unnecessary.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with an electrically heated device, of a thermostat arranged to control an electric circuit to regulate the temperature of said device, automatic time control means, connecting means including means normally maintaining said circuit closed, and cooperating means operated to open said circuit by the connection of said time control means whereby said automatic time control means may be connected in said circuit.

2. The combination with an electrically heated device, of a thermostat arranged to control an electric circuit to regulate the temperature of said device, automatic time control means, and connecting means whereby said automatic time control means may be connected in said circuit, said connecting means comprising contacts normally in engagement to maintain said circuit closed but separated by the connection of said automatic time control means.

3. The combination with an electrically heated device, of a thermostat arranged to control an electric circuit to regulate the temperature of said device, automatic time control means, quick detachable means whereby said time control means may be connected in said circuit, and means cooperating With said quick detachable means for closing said circuit when said time control means is disconnected.

4. The combination with an electrically heated device, of a thermostat arranged to open and close an electric circuit to regulate the temperature of said device, automatic time control means, and a quick detachable connection whereby said time control means may be connected in said circuit, said quick detachable connection comprising contacts normally in engagement to maintain said circuit closed, and means for separating said contacts and for including said time control means in said circuit.

5. An attachment for electrically heated devices provided with a control circuit, comgrising automatic time control means, quick etachable means for connecting said automatic time control means in said control circuit, and means biased to closed position for closing said control circuit when said time control means is disconnected.

6. An attachment for electrically heated devices provided with a thermostatically controlled circuit, comprising automatic time control means, means for connecting said automatic time control means in said circuit, and means for automatically closin said control circuit when said time contro means is disconnected.

7. The combination with an electrically heated range of a thermostat arranged to control an electric circuit to regulate the temperature of said device, a contact receptacle on said range provided with contacts normally in engagement to maintain said control circuit closed, automatic time control means, and a plug arranged to cooperate with said receptacle to separate said contacts and connect said time control means in said circuit.

8. The combination with an electrically heated range of a thermostat arranged to control an electric circuit to regulate the temperature of said range, a pair of flexible contact clips connected in said circuit, contacts carried by said clips normally in engagement to establish said circuit, automatic time control means, and spaced plug contacts connected to said time control means cooperating with said clips to separate said contacts and thereby connect said time control means in said circuit.

In witness whereof, I have hereunto set my hand.

FRANCIS H. MCCORMICK. 

